I'll copy and paste my review written the other day. I own Platinum (Protein Leather), Sheepskin and Hybrid for TH-X00. With and without attenuation ring, I actually prefer all 3 without the ring, it just makes it sound too "thick" with it on. Though Sheepskin mightttttt be ok with the ring.
Platinum (Protein Leather): Closest to stock sound, smoothed treble, mids is a tiny bit further than stock, bass a little bit boomy, biggest sound stage.
Sheepskin: Clean sounding, treble a little bit shaved off, mids is similar to Platinum, mid bass is recessed (probably why it sounds clean, but loses warmth), bass is THICK, didn't notice much to sound stage.
Hybrid: Treble a bit sharp, mid recessed, bass also sound THICK, didn't notice much to sound stage. Which is surprising because I was hoping hybrid would make the vocal more forward but it's the opposite.
All in all I find surprisingly I like Platinum the best (also cheapest, since it's fake leather, but it might explain why it sound closer to stock pad). After that I think Sheepskin with attenuation ring might be ok (forgot if I prefer with or without), and lastly Hybrid pad (disappointing since I had high hope for it).
BUT!!!!! (huge butt, very important) Unless stock pad really irritates you, I'd stick with it. Stock pad to me sound the best and most balanced (also free since it came with headphone). Any other pad just sound "odd" to me (though Platinum is closest, also improves sound stage at the trade off of boomier bass).
I gave 4 star because build quality and customer service is very very good. Unfortunately I had to deduct a star because in the end I didn't end up using them (stock pad sound the best). So unless comfort is really bad for you (for me it's fine) then I would just keep the stock pad.